This new study, conducted by the University of Michigan, also found that high-carb meals sustain insulin resistance, the cause of prediabetes and type 2 diabetes.

Michigan researchers wanted to assess the involvement of dietary carbohydrate, especially when timed after exercise, and how this affected four groups of eight metabolically healthy weight-matched postmenopausal women.

The women were divided into four groups and given meals of either 30 or 60 per cent carbohydrates with or without moderate-intensity exercise beforehand. The low-and high-carb meals had the same calorie counts.

Researcher Katarina Borer reported that the low-carb group showed a reduction in insulin resistance after the third meal in the evening; the high-carb group experienced sustained high post-meal insulin.

She explained the meals fed to the high-carb group were in line with the 45-to-65 per cent daily carbohydrate intake recommended by dietary guidelines in the US.

"We showed an acute, one-day reduction in insulin resistance after the third low-carbohydrate meal eaten in the evening, so one could argue that this is transient and insignificant," Borer said.

"But at least two other studies where high-carbohydrate meals were fed to volunteers for five and for 14 days show that the outcome was worrisome.

"These subjects developed increased fasting insulin secretion and insulin resistance, increased glucose release by the liver which produced high blood sugar, and dramatically lowered fat oxidation that contributes to obesity. These then were more persistent effects that could be a path to prediabetes and diabetes."

Furthermore, exercise did not lower insulin resistance in either group, so the findings suggest that the insulin reaction was driven by the effect of carbohydrate. But Borer added that this doesnt mean exercise doesn't influence insulin action.

Editors note: Diabetes.co.uk has long championed the low-carb diet for people with diabetes, which is why we launched the Low Carb Program. After six months, people who complete the program have an average HbA1c improvement of 1.1%.